09/20/1993

Bright Future for Alabama Ornamental Fish

AUBURN, Ala. - As anyone who has ever bought tropical fish can attest, there's money in those aquariums. And, following the old adage, "you are what you eat," an Auburn University researcher says proper feed ingredients may be the key to making money in Alabama's growing tropical fish industry.

A fisheries researcher with the Alabama Agricultural Experiment Station, Patricia Duncan says all aspects of the tropical fish hobby are increasing. She adds, "Although the multi-million dollar industry is centered in Florida, more Alabama fish farmers are getting into koi carp and goldfish production, especially with the increase in popularity of backyard ponds."

But the industry isn't without its problems. One of the biggest is that little is known about tropical fish nutrition. Much of what is known has been borrowed from nutritional studies of catfish, salmon, and other food fish species.

"One problem is that ornamental fish breeders try to use ready-made food fish formulations for the young fish, or fry," she says. "But there is a lack of information on what these type fish need. And commercial foods don't have color pigments, because the farmers just need the fry to grow."

For some species, such as salmon, color becomes important and is added as the fish grow. But finding the requirements and vitamins necessary for fish health is long, complex work. Duncan has learned enough to be able to identify several vitamin deficiencies in fish, as well as pinpoint some of their other ailments. She has a firm belief that many fish diseases are related to nutrition.

Her belief is further strengthened by a second problem; the recirculating water systems used by many of the best tropical fish breeders. The traditional tropical fish growing systems used small ponds that were covered during the winter. The ponds had plenty of natural food in the form of insects, invertebrates, and algae. And the fish had plenty of color.

But some of the more advanced farmers moved to completely enclosed recirculating water systems. These systems enabled them to grow thousands of fish, and to control every aspect of production--water quality, temperature, breeding and more. But it was in these high-tech arenas that fish first began losing their color.

"The same thing often happens in aquariums," says Duncan. But the average hobbyist, unlike the grower, isn't going to lose their business if their fish fade.

Duncan doesn't look at the industry through rose-colored glasses. Instead, she sees the work through a mixture of marigold, paprika, red pepper and blue-green algae extracts and concentrations. She is studying both synthetic and natural compounds to add color to tropical fish.

"The poultry industry has long used pure synthetic and some natural carotenoid extracts to enhance the color of broiler skins for market," she says. "But interest is growing in using natural carotenoid pigments and extracts, primarily because of their lower cost."

Carotenoids, for example, are well-known for producing the orange color in carrots--but they are also present in broccoli and green peppers, as well as sweet red peppers. And carotenoids are just as important to tropical fish for color enhancement.

For the studies, Duncan has duplicated the recirculating systems of the producers on a small scale in her laboratory. Her fish diets are made with varying concentrations of pigments added to determine the proper dosage for the best colors. Her work has been done for many years by cooperative agreements with several tropical fish farmers and companies.

"Tilapia, while not usually considered an aquarium fish, are nevertheless tropical, and are ideal model fish," she says. "Much of the work on color can be attributed to tilapia, which are usually marketed with natural black-barred skin or body color. American consumers, however, are more accustomed to eating light-colored, or solid fish. The first color experiments at Auburn were with tilapia, and resulted in a solid-golden colored fish for food."

The cooperative agreements have allowed her to work with a variety of fish species. Angelfish, which are in the same family as tilapia, are also being studied; Duncan notes that cichlids are another popular tropical fish that are also related to tilapia. Tiger and cherry barbs are also included in the project.

"Think about it. Many community tanks--where mixtures of different species are kept together in one environment--are composed of fish that are not related and that come from all over the world. Why do we think one type of food will satisfy the requirements of all these different fish?"

Duncan is both surprised and pleased by the intense interest in the work by tropical fish producers. In the future, she would like to examine the link between nutrition, the immune response system, and the health of fish.

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
by Reginia Broadway

September 20, 1993